Voice Tool On Enterprise Network

Enterprise Network is an interconnection of LANs belonging to different departments in an enterprise via WAN such as ISDN, DDN, and Internet and so on. Since ISDN have the advantages of higher transmission rate and lower charge for communication than others, I concentrate my research in this thesis on some key problems of voice over Enterprise Network based on ISDN. Since Enterprise Network is hybrid architecture and its special using network bandwidth is limiting and can be controlled, there are many new challenges that had to be faced. The challenges are how to take the full advantage of the transmission capacity of LANs to avoid the congestion on WAN, how to support conversation among multiple parts, how to make use of limiting network bandwidth efficiently and how to support multiple work patterns and multiple floor control modes to meet requirement of cooperative work in the enterprise environment.The main contribution of this paper is described as the following:1. ISDN can not meet the demand of conversation among multiple parts because it does not support multicast directly. The voice application systems existing can support multiple parts conversation by serial communication or by MCU (Multiple-point Control Unit) transmission. For the former, time-delay will increase along with the number of participants. For the latter, costly hardware is needed. The difference of transmission capability between WAN and LAN has not been considered in the two methods. Group communication based on agent is introduced according to hybrid architecture of Enterprise Network. Irresponsible multicast mechanism transfers audio data to...